1. Field of the Invention
The present invention relates to tetracoordinated or pentacoordinated tin(IV) compounds useful, in particular, as latent catalysts in the preparation of polyurethanes and for the crosslinking of organopolysiloxanes.
2. Description of the Prior Art
Numerous tin compounds are known to this art which are useful as catalysts, in particular for:
(i) the synthesis of polyurethanes; exemplary thereof are the tin chelates (U.S. Pat. No. 3,055,845) and the products of the reaction between a tin(IV) carboxylate and a sulfonylisocyanate (DE-A-3,326,566 and EP-A-232,541);
(ii) the crosslinking of silicone polymers by a polycondensation reaction; exemplary thereof are the dialkyl-tin dicarboxylates (Noll, Chemistry and Technology of Silicones, page 337, Academic Press, 1968--2nd edition), and the dialkyl-tin bischelates (EP-A-147,323 and U.S. Pat. No. 4,517,337).
Tetracoordinated tin(IV) compounds useful as latent catalysts ar described in published French Patent Applications 88/05,554 and 88/05,555, filed Apr. 21, 1988 and assigned to the assignee hereof.